FIELD OF THE INVENTION
The subject of the present invention is a method for fuel injection for starting an internal combustion engine and, more specifically, a method allowing quick jolt-free starting even at very low temperature.
Multi-cylinder four-stroke internal combustion engines are currently operated on the so-called sequential injection principle. In this method, one injector is associated with each cylinder and this injector is operated on the basis of the angular position of the engine in the cycle so that a predetermined amount of fuel is injected into each cylinder at a precise phase in the engine cycle. To achieve this, the position of the engine is recognized on the basis of signals supplied by sensors associated with targets linked to the crankshaft and to the cam-shaft. The cylinder which is to begin its induction phase is determined, and the injector associated with this cylinder is operated in such a way that the desired amount of fuel is injected before the start of the induction phase.
However, during engine starting, the exact position of this engine is not known. A device designed to implement a method for injection for an internal combustion engine in such a way that on closure of an engine starting contact a first amount of fuel is injected simultaneously into all of the cylinders and when an engine synchronization signal is recognized the fuel is injected sequentially, one cylinder at a time, once per cycle and in a predetermined order is known from French Patent Application 2 516 982.
It has, however, been observed that misfires could occur in one of the cylinders and lead to the engine slowing down and even sometimes stalling, particularly under extreme cold start conditions.